You are viewing the page for Apr. 19, 2011
  Select another date:
<<back forward>>
SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
 
Solar wind
speed: 427.7 km/sec
density: 0.6 protons/cm3
explanation | more data
Updated: Today at 2343 UT
X-ray Solar Flares
6-hr max: B7
1841 UT Apr19
24-hr: C1
0512 UT Apr19
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 19 Apr 11
Sunspot 1193 is big but quiet, producing just a smattering of low-level C-class flares in the past 24 hours. Credit: SDO/HMI

more images: from Dave Gradwell of Birr Ireland
Sunspot number: 67
What is the sunspot number?
Updated 18 Apr 2011

Spotless Days
Current Stretch: 0 days
2011 total: 1 day (<1%)
2010 total: 51 days (14%)
2009 total: 260 days (71%)
Since 2004: 820 days
Typical Solar Min: 486 days

Updated 18 Apr 2011


The Radio Sun
10.7 cm flux: 111 sfu
explanation | more data
Updated 18 Apr 2011

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/POES
Planetary K-index
Now: Kp= 1 quiet
24-hr max: Kp= 2
quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 11.0 nT
Bz: 2.6 nT south
explanation | more data
Updated: Today at 2346 UT
Coronal Holes: 19 Apr 11
A solar wind stream flowing from the indicated coronal hole should reach Earth on or about April 20th. Credit: SDO/AIA.
SPACE WEATHER
NOAA Forecasts
Updated at: 2011 Apr 19 2200 UTC
FLARE
0-24 hr
24-48 hr
CLASS M
15 %
15 %
CLASS X
01 %
01 %
Geomagnetic Storms:
Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm
Updated at: 2011 Apr 19 2200 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
35 %
25 %
MINOR
10 %
05 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
30 %
30 %
MINOR
15 %
10 %
SEVERE
05 %
01 %
 
Tuesday, Apr. 19, 2011
What's up in space
 

Are we alone? Your iPhone has the answer. Download the all-new Drake Equation app to calculate the population of the Milky Way.

 
DrakeEQ for iPhone and iPad

SPACE STATION FLYBYS: The International Space Station (ISS) is making a series of bright flybys over Europe and North America this week. It outshines everything in the evening sky except the Moon. Sky watchers in the USA and Canada, check your cell phone for flyby times. Predictions are also available on the web.

ISS images: from Paco Bellido of Cordoba, Spain; from Jayme Hanzak of Cedar Grove, North Carolina; from Jasper Mitchin of Worthington, Ohio

SPACE STATION RADAR ECHO: The Air Force Space Surveillance Radar in Texas is scanning the skies above the USA for Earth-orbiting objects. Last night, the International Space Station flew through the radar's primary beam, producing a strong echo. Click to listen:


Multimedia: audio file (1 MB wav), dynamic spectrum

Because the ISS is traveling at 17,000 mph, the echo sounds Doppler-shifted like the whistle of a moving train. The physics of Doppler shifts works the same in Earth orbit as it does on Earth.

Radio engineer Stan Nelson recorded the echo from his backyard listening post in Roswell, New Mexico. "The ISS passed almost directly over Lubbock, TX--perfect geometry for sending the echo in my direction," he says. The next favorable radar pass occurs on April 19 at 8:37 pm - 8:42 pm CDT. Stay tuned for live ISS echoes on SpaceWeather Radio.

AURORA WATCH: April continues to be a good month for auroras. A new display could begin on April 20th when a solar wind stream is due to hit Earth's magnetic field. Wayne Barsky sends this dynamic preview from the Alaskan Arctic:

"To create the video sequence, I assembled a series of still frames taken over the course of almost four hours on the morning of April 1, 2011," says Barsky. "It was a moonless and brutally cold (-23 F) night. At one point, I was checking one of my camera settings and the metal end of my penlight froze to my tongue!"

Readers in the Arctic: Beware the penlight and remain alert for auroras.

April 2011 Aurora Gallery
[previous Aprils: 2010, 2009, 2008, 2007, 2006, 2005, 2004, 2003, 2002]

  Near Earth Asteroids
Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.
On April 19, 2011 there were 1218 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Mag.
Size
2011 GP59
Apr 15
1.4 LD
--
58 m
2002 DB4
Apr 15
62.5 LD
--
2.2 km
2011 GJ3
Apr 27
7.7 LD
--
24 m
2008 UC202
Apr 27
8.9 LD
--
10 m
2009 UK20
May 2
8.6 LD
--
23 m
2008 FU6
May 5
75.5 LD
--
1.2 km
2003 YT1
May 5
65.3 LD
--
2.5 km
2002 JC
Jun 1
57.5 LD
--
1.6 km
2009 BD
Jun 2
0.9 LD
--
9 m
2002 JB9
Jun 11
71.5 LD
--
3.2 km
2001 VH75
Jun 12
42.2 LD
--
1.1 km
2004 LO2
Jun 15
9.9 LD
--
48 m
2001 QP181
Jul 2
35.1 LD
--
1.0 km
2011 GA55
Jul 6
64 LD
--
1.0 km
2011 EZ78
Jul 10
37.3 LD
--
1.5 km
2003 YS117
Jul 14
73.9 LD
--
1.0 km
2007 DD
Jul 23
9.3 LD
--
31 m
Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU. MAG is the visual magnitude of the asteroid on the date of closest approach.
  Essential web links
NOAA Space Weather Prediction Center
  The official U.S. government space weather bureau
Atmospheric Optics
  The first place to look for information about sundogs, pillars, rainbows and related phenomena.
Solar Dynamics Observatory
  Researchers call it a "Hubble for the sun." SDO is the most advanced solar observatory ever.
STEREO
  3D views of the sun from NASA's Solar and Terrestrial Relations Observatory
Solar and Heliospheric Observatory
  Realtime and archival images of the Sun from SOHO.
Daily Sunspot Summaries
  from the NOAA Space Environment Center
Heliophysics
  the underlying science of space weather
Conquest Graphics
  for out-of-this-world printing and graphics
Science Central
   
  more links...
©2010 Spaceweather.com. All rights reserved. This site is penned daily by Dr. Tony Phillips.
©2019 Spaceweather.com. All rights reserved.